Technical Field
The present invention relates to mattresses generally, and more particularly to a novel and improved lightweight flotation mattress designed to reduce the surface pressure that is created when a patient is confined on the mattress for long periods of time, or for burn patients.
Bedridden patients in hospitals, nursing homes, and in home care situations often develop decubitus ulcers as a result of their confinement. In an attempt to prevent the formation of decubitus ulcers or bed sores, a number of flotation mattresses have been designed to provide enhanced support for bedridden patients. A large number of these flotation mattresses embody water flotation systems providing a type of support which permits bed sores to be successfully treated and healed. However, water flotation mattresses have been subject to a number of disadvantages which have proven difficult to overcome. For example, most of these mattresses require special supporting frames capable of sustaining the weight of a water-filled flotation mattress. Consequently, such flotation mattresses are either not designed for use on conventional hospital beds, or when such use is possible, adversely affect the operation of the hosptial beds. The normal hospital bed is not designed filled flotation mattress in addition to the weight of the patient, and such mattresses are not capable of flexing with a hospital bed when it is moved to a raised position.
In the past, attempts have been made to lower the weight of a water-filled flotation mattress so that the mattress can be supported on a hosptial bed. For example, U. S. Pat. No. 3,848,282 to E. A. Viesturs discloses a lightweight flotation mattress wherein tie strips internally positioned within the mattress limit the amount of water needed to fill the mattress and, thus, the mattress weight. The same patent discloses eliminating the pillow area of the mattress to further reduce the weight of the water needed to support the patient. Also, U.S. Pat. Nos. 4,534,078 to Viesturs et al, 4,501,036 and U.S. Pat. No. 4,513,463 to Santo disclose water-filled mattresses having peripheral air chambers. With portions of the mattress being filled with pressurized air, the overall weight is somewhat reduced.
Also, U.S. Pat. No. 3,766,579 to Shields discloses a water bed having a compartmentalized air beam structure combined with a water mattress. This structure is of less weight than a similar structure completely filled with water, as is the flotation mattress shown by U.S. Pat. No. 4,517,692 to Vogel which incorporates a foam frame in combination with a water-filled mattress structure.
Although these prior art flotation mattress structures have, to some extent, successfully reduced the overall flotation mattress weight, the structures are still often quite heavy. One solution to the problem of weight is the total elimination of water, approximating its element of support by using internal air beam structures within an outer air mattress as disclosed in U.S. Pat. No. 3,705,429 to Nail.
A universal problem with known flotation mattresses is the lack of ventilation provided to the patient supported thereby. Since these mattresses must be formed from waterproof material, there is no opportunity for air to pass through the mattress and reach the patient. The failure to ventilate the patient's body offsets, to some degree, the beneficial action of flotation mattresses in treating or preventing decubitus ulcers. Some early attempts were made to provide ventilation compartments within water-filled mattresses, as illustrated by U.S. Pat. No. 529,852 to Brupbacher, but enclosed ventilation compartments of the type shown by this patent having little access to the outside atmosphere are only minimally effective. Likewise, U.S. Pat. No. 3,089,153 to Bosc disclosing an air mattress of alternating air -filled chambers with ventilation chambers suffers the same limitation.